1. Field of the Invention
The present invention relates to the field of pharmaceutical compositions, particularly to a process and composition containing pamabrom and pyrilamine maleate.
2. Description of the Background Art
Many pharmaceutical compositions contain a combination of ingredients. Different compounds can be combined into a single pharmaceutical formulation so as to enhance the effectiveness of one or more of the compounds. Alternatively, a pharmaceutical composition can contain different compounds for treatment of a variety of symptoms.
Pamabrom is a diuretic, and is described in expired U.S. Pat. No. 2,711,411. Pamabrom is a fine white powder which decomposes at about 300.degree. C., and has a solubility in water of greater than 30 g/100 ml at 25.degree. C. A saturated aqueous solution of pamabrom has a pH of from about 8.0 to 8.5. Merck Index, entry no. 6865, 10th ed., p 1005 (1983).
Pyrilamine is an antihistaminic pharmaceutical which is described in expired U.S. Pat. No. 2,502,151. Pyrilamine maleate forms crystals which are stable in air, having a melting point of about 100.degree.-101.degree. C. One gram of pyrilamine maleate dissolves in about 0.4 ml water and a 10% solution thereof has a pH of about 5.1. Pyrilamine maleate can precipitate to the oily, free base at a pH of 7.5-8.0. Merck Index, supra. entry no. 7883, p. 1152.
Acetaminophen is an analgesic and antipyretic described in expired U.S. Pat. No. 2,998,450. Acetaminophen forms large monoclinic prisms from water, and has a melting point of about 169.degree.-170.5.degree. C. Acetaminophen is very slightly soluble in cold water and considerably more soluble in hot water. Merck Index, supra, entry no. 39, p. 7. Acetaminophen is one of the most widely used over-the-counter analgesics, and it is highly desirable to form pharmaceutical compositions containing acetaminophen and other pharmaceutical compounds.
In view of the diuretic activity of pamabrom and the antihistaminic activity of pyrilamine maleate, it would be desirable to combine these compounds in certain pharmaceutical compositions. Furthermore, because of the analgesic and antipyretic activities of acetaminophen, it would be desirable to combine acetaminophen with pamabrom and pyrilamine maleate in a single pharmaceutical composition.
Additionally, in view of the threat of product tampering, it is highly desirable to be able to form tablets from pharmaceutical compositions containing more than one active ingredient.
One method of manufacturing pharmaceutical compositions containing two or more active ingredients is to prepare separate formulations containing the respective active ingredients, and then dry blending the formulations together to achieve the desired active ingredient levels. However, from a processing standpoint, it is often more desirable to produce one formulation containing all active ingredients utilizing a single process.
There thus remains a need in the art for tablettable pharmaceutical compositions containing more than one active ingredient.